关键词: 溴氰菊酯, 中华绒螯蟹, 急性毒性, 氧化胁迫指标, 肝胰腺组织结构

Abstract: In order to explore the toxicological effects and mechanism of deltamethrin on Eriocheir sinensis, an acute semi-static toxic test was carried out, the LC₅₀ values of 24, 48 and 96 h were 4.289 4, 3.481 8 and 1.319 5 μg·L^-1, respectively, and the safe concentration was 0.658 9 μg·L^-1. This study also revealed the modulation of antioxidant enzymes such as superoxide dismutase(SOD), catalase(CAT) and malondialdehyde (MDA) content, which was the main product of lipid peroxidation, at 6, 12, 24, 48 and 72 h in different deltamethrin concentration. 96 h-LC₅₀/2(concentration I) group, 96 h-LC₅₀/5(concentration II) group and 96 h-LC₅₀/10(concentration III) group were test groups, and blank group and vehicle group were control groups. Histological structure of hepatopancreas was observed on 15^th day in different deltamethrin concentrations. The results were as follows: (1) The oxidative stress indicators were varied in all groups exposed to deltamethrin, SOD and CAT activities showed similar variation of inhibition-induction-inhibition during the test, and the levels of MDA in test groups were all higher than that in blank group. The three indicators had no significant difference at different time in both vehicle group and blank group, and vehicle group also had no obvious difference from blank group. After 6 h exposed to deltamethrin, the CAT activities of all test groups were significantly lower than those of control group, and CAT activities of concentration II and III groups decreased by 37.96% and 38.92% compared with blank groups. MDA levels of test groups were obviously higher than that of control group. After 12 and 24 h, SOD and CAT activities were induced, SOD activities of three test groups were 72.13%, 87.93% and 83.20% higher than that of blank group, and the levels of MDA decreased at 24 h. After 48 h and 72 h, SOD and CAT activities were inhibited again, SOD activities of concentration I and III groups were 40.94% and 51.06% lower than that of blank group, CAT activities of concentration III group were 32.85% lower than that of blank group, and MDA levels of test groups gradually increased along with the increase of stress time of deltamethrin. (2) Histological structure of hepatopancreas was affected at different degrees in different deltamethrin concentration for 15 d. In these three test groups, the number of B cells of hepatopancreas was decreased, the basement membrane became thicker, some hepatic cells were swelling and cavity appeared, some vacuoles appeard in B cells. As deltamethrin concentration increased, the degree of deterioration of hepatopancreas aggravated, the number of vacuoles increased and some hepatic cells were crushing and many cell debris appeared in the lumen, many vacuoles existed between basement membrane and epithelial cells, part of the basement membranes were separated from epithelial cells and ruptured, nucleus were pyknotic. The results indicated that deltamethrin was high toxic pesticide to E.sinensis, with the deltamethrin concentration increasing and stress time prolonging, MDA levels increased, and the non-specific defense system and normal cell structure of E. sinensis were destroyed.

Key words: deltamethrin, Eriocheir sinensis, acute toxicity, oxidative stress indicators, hepatopancreas structure